1. Field of the Invention
This invention relates to ham loaf size sensing means in a hamloaf slicing machine.
2. Prior Art
Ham loaves are usually machine sliced and then packaged into units of packages suitable for retail sale, each package usually having a content ranging from several slices to more than ten slices. The selling price per package is determined by the weight of the sliced ham content and the price per unit weight. Therefore, it is necessary that the weight of the sliced ham content per package must meet a predetermined weight requirement. More specifically, actual weight A' of the sliced ham content of the package must be equal to the prescribed weight A indicated on each package ( A'=A) or in plus relation to the prescribed weight A ( A'&gt;A); in no way is the former weight allowed to be in minus relation to the latter weight ( A'&lt;A).
Now, in one known ham loaf slicing maching, a ham loaf supported in an upright or slightly inclined condition is fed downwardly at a predetermined speed by a pair of conveyors arranged in opposed relation along the longitudinal direction of the ham loaf while it is held between the conveyors, and as the end of the ham loaf advances into a slicing station, it is cut off to a predetermined thickness by a cutter rotating at constant speed.
Therefore, if ham loaves are uniform in thickness, ham slices cut by such slicing machine must be constantly uniform in weight. Actually, however, not every ham loaf manufactured has satisfactory roundness in its cross-sectional configuration. It is also true that no ham loaf has uniform thickness ( cross-sectional area ) throughout its entire length. In the manufacture of ham loaves, at present, it is extremely difficult to uniformize various parts of each ham loaf in their cross-sectional dimensions, much more is it difficult to produce ham loaves which are completely uniform in size.
Therefore, it has been impossible to constantly obtain ham slices of uniform weight by employing such slicing machine even if slicing accuracy were improved in terms of sliced ham thickness. As such, a matter of great concern to sliced ham producers has been how actual per-package weight A' of machine sliced ham could be brought closer to the prescribed per-package weight A on the plus ( A'&gt;A ) side.
This problem can be solved by solved by providing at a position prior to the slicing station a suitable sensing device which can constantly sense variations in cross-sectional area of a ham loaf at a location adjacent the slicing station, whereby the rate of ham loaf feed toward the slicing station is controlled according to the variation in ham loaf cross-sectional area detected. That is, the advancing speed of the ham loaf is increased with respect to its portions having a relatively small cross-sectional area, whereas the advancing speed of the ham loaf is lowered with respect to its portions having a relatively large cross-sectional area. In this way, ham slices can be cut thinner where they are diametrically larger, and can be cut thicker where they are diametrically smaller, it being thus possible that actual per-package weight A' of ham slices is brought closer to the prescribed per-package weight A on the plus ( A'&gt;A ) side, with less variation in weight.
Several food loaf slicing machines having such food loaf size sensing device and a food loaf feed rate control device, whereby possible variations in sliced food weight are prevented, are disclosed in U.S. Pat. Nos. 3,105,533; 3,144,893; and 4,428,263.
Of these, the food loaf slicing machine disclosed in U.S. Pat. No. 4,428,263 includes such arrangement for detecting the size of a food loaf product, such as ham loaf, as shown in FIGS. 6 and 7, which comprises a collar 55 encompassing the ham loaf 51 at the entrance to the slicing station 52 as the lower end of the loaf fed downwardly by a pair of feed conveyors 53, 54 enters the collar, the collar being of transverse split construction, including first and second collar members 55.sub.1, 55.sub.2. More specifically, the ham loaf size sensing arrangement comprizes the first collar member 55.sub.1 being movable toward and away from the second collar member 55.sub.2 in a direction transverse to the path of ham loaf movement, a biasing means connected to the first collar member 55.sub.1 ( movable collar member ) for biasing it toward the second collar member 55.sub.2 ( fixed collar member ) to maintain both collar members in predetermined limited pressure engagement with the lower end of the feed loaf, and a loaf size sensor 57 connected to the first collar member 55.sub.1 for sensing movements of the first collar member 55.sub.1 indicative of variations in cross-sectional area of the ham loaf 51 passing through the space between the collar members 55.sub.1 and 55.sub.2.